Benchmark: map vs foreach 2023

Tests:

map
let myArr = ["69", "108", "122", "101", "114", "111"], result = myArr.map((item) => String.fromCharCode(item)).join(""); console.log(result);
foreach
let myArr = ["69", "108", "122", "101", "114", "111"], result = ""; myArr.forEach((item) => (result += String.fromCharCode(item))); console.log(result);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
foreach

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 120 on Android

View result in a separate tab

Test name	Executions per second
map	26238.5 Ops/sec
foreach	27222.9 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and the pros/cons of each approach.

**Benchmark Overview**

The benchmark compares two approaches for mapping over an array of characters: `map()` and `forEach()`. The test case uses a predefined JavaScript array containing ASCII values of characters, which are then converted to their corresponding Unicode characters using `String.fromCharCode()`.

**Options Being Compared**

1. **`map()`**: This method returns a new array with the results of applying the provided function on every element in this array.
2. **`forEach()`**: This method executes the provided callback function once for each element in an array.

**Pros and Cons**

* `map()`: Pros:
	+ Returns a new array, which can be more efficient if you need to use the result later.
	+ Allows for more concise code, as it returns a value directly.
Cons:
	+ Creates a new array, which can lead to memory overhead if working with large datasets.
	+ May not be suitable for operations where side effects are expected (e.g., modifying the original array).
* `forEach()`: Pros:
	+ Does not create a new array, making it more memory-efficient for large datasets.
	+ Suitable for operations where side effects are expected.
Cons:
	+ Returns `undefined`, which may require additional processing to access the result.

**Library and Special JS Features**

In this benchmark, no specific libraries or special JavaScript features are used. The test case relies solely on built-in JavaScript methods (`map()`, `forEach()`, and `String.fromCharCode()`).

**Other Considerations**

When choosing between `map()` and `forEach()`, consider the following:

* Use `map()` when you need to process an array to produce a new array, or when you want to return a value directly.
* Use `forEach()` when you need to execute a callback function for each element in an array, such as iterating over an array without modifying it.

**Alternatives**

If you're looking for alternative approaches to map over arrays, consider:

1. **`Array.prototype.reduce()`**: Similar to `map()`, but returns a single value (the accumulator) instead of an array.
2. **`for...of` loop**: An older approach to iterating over arrays, which can be more concise but less efficient than `forEach()` or `map()`.
3. **Using `Array.prototype.filter()` and `Array.prototype.slice()`**: If you need to filter out elements from the original array, consider using `filter()` and then slicing the resulting array.

Keep in mind that these alternatives may have different performance characteristics and use cases compared to `map()` and `forEach()`.

Related benchmarks:

map vs foreach 2023 (version: 0)

Comparing performance of: map vs foreach

Created: 2 years ago by: Guest

Jump to the latest result

map

foreach

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):